Electrochemical cells and methods for making same

ABSTRACT

The present disclosure is directed to electrochemical cells having injection molded or 3D printed components, such as cathodes, anodes, and/or electrolytes, and methods for making such electrochemical cells. The cathodes, anodes, and/or electrolytes can be formed from a binder resin and various conductive and active materials, mixtures of which are injected into a mold under heat and pressure to form the components of the electrochemical cells. The cathode can include conductive metallic powder, flakes, ribbons, fibers, wires, and/or nanotubes. Further, electrochemical arrays can be formed from multiple electrochemical cells having injection molded or 3D printed components.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of and claims priority toU.S. patent application Ser. No. 15/437,722, entitled “ELECTROCHEMICALCELLS AND METHODS FOR MAKING SAME,” which was filed Feb. 21, 2017 andwhich claims priority to U.S. Provisional Patent Application No.62,396,648, entitled ELECTROCHEMICAL CELLS AND METHODS FOR MAKING SAME,”which was filed Sep. 19, 2016. The aforementioned applications arehereby incorporated by reference herein in their entirety

FIELD

The present disclosure generally relates to methods of makingelectrochemical cells, and more particularly, to methods of formingelectrochemical cells having molded electrodes and/or electrolytes.

BACKGROUND

Conventional electrical batteries, capacitors, and fuel cells aretypically formed using stamped metal insert molding connectors and/or alayering process using several different material types, in severaldifferent forms (powder, liquid, solid), with no particular physicalcommonality. As such, conventional batteries may develop decreasedcharge capacity due to the separation of the anode and cathode from theelectrolyte within the case of the battery.

As a conventional, solid state battery is charged and discharged, theanode and cathode can begin to separate from the electrolyte, creatingvoids between the interfaces of the electrodes and electrolyte. Air mayenter these voids, causing separation of the electrodes from theelectrolyte. This separation may reduce the efficiency and/or output ofthe battery.

As the use of batteries, capacitors and fuel cells to power devicesincreases, a need exists for more reliable and robust batteries,capacitors, and fuel cells that have an increased charge density and/orincreased charging life. Further, conventional batteries may benefitfrom improved methods of manufacture that result in greater structuralintegrity against vibration and impact.

SUMMARY

The present disclosure includes methods for forming an electrochemicalcell comprising injecting, via injection molding, a mixture of a binderresin, a cathode conductive material, and a cathode active material intoa first cavity of a mold under heat and pressure to form a firstcathode; injecting, via injection molding, a mixture of the binder resinand a first conductive material into a cavity within the first cathodeunder heat and pressure to form a cathode current collector and acathode bus; injecting, via injection molding, a mixture of the binderresin and an anode conductive material into a second cavity of the moldunder heat and pressure to form a first anode; injecting, via injectionmolding, a mixture of the binder resin and a second conductive materialinto a cavity within the first anode under heat and pressure to form ananode current collector and an anode bus; injecting, via injectionmolding, a mixture of the binder resin and an electrolytic materialbetween the first anode and the first cathode under heat and pressure toform a first electrolyte; and forming a case surrounding at least aportion of the first cathode, the first anode, and the firstelectrolyte. The cathode material and the anode material can comprise atleast one of styrene butadiene copolymer, polyvinylidene fluoride,polyurethane, polyvinylchloride, high density poly ethylene, polymethylmethacrylate, ethylene vinyl acetate, polyethylene oxide, low densitypolyethylene, and linear low density polyethylene. The cathodeconductive material can comprise at least one of a metallic powder, ametallic flake, a metallic ribbon, a metallic fiber, a metallic wire,and a metallic nanotube, and can comprise between about 50 and 70percent by volume. Further, the cathode conductive material can comprisea combination of lithium and at least one of cobalt, manganese,nickel-cobalt-manganese, and phosphate. The anode conductive materialcan comprise at least one of a graphite powder, a graphite fiber, and acarbon nanotube, and may be between about 75 and 85 percent by volume ofthe first anode. The electrolyte can comprise at least one of LiBF₄,LiBF₆, LSPS, LiCoO₂, LiOHH₂O, Li₂CO₃, and LiOH. The case can comprise anon-conductive thermoplastic material.

The present disclosure further includes an electrochemical cellcomprising a first cathode comprising a thermoplastic cathode materialhaving a cathode conductive material and a cathode active materialsuspended within the thermoplastic cathode material, wherein the cathodeconductive material comprises between 50 and 70 percent by volume of thefirst cathode, a first anode comprising a thermoplastic anode materialand an anode conductive material suspended within the thermoplasticanode material, wherein the anode conductive material comprises between75 and 85 percent by volume of the first anode, a first electrolytepositioned between the first cathode and the first anode and comprisinga thermoplastic electrolyte material and an electrolytic material, and acase surrounding at least a portion of the first cathode, a portion ofthe first anode, and a portion of the electrolyte. The cathode materialand the anode material can comprise at least one of styrene butadienecopolymer, polyvinylidene fluoride, polyurethane, polyvinylchloride,high density poly ethylene, polymethyl methacrylate, ethylene vinylacetate, polyethylene oxide, low density polyethylene, and linear lowdensity polyethylene. The cathode conductive material can comprise atleast one of a metallic powder, a metallic flake, a metallic ribbon, ametallic fiber, a metallic wire, and a metallic nanotube. Further, thecathode conductive material can comprise a combination of lithium and atleast one of cobalt, manganese, nickel-cobalt-manganese, and phosphate.The anode conductive material can comprise at least one of a graphitepowder, a graphite fiber, and a carbon nanotube. The electrolyte cancomprise at least one of LiBF₄, LiBF₆, LSPS, LiCoO₂, LiOHH₂O, Li₂CO₃,and LiOH. The case can comprise a non-conductive thermoplastic material.

The present disclosure includes methods for forming an electrochemicalcell comprising printing, via 3D printing, a first cathode from acathode filament comprising a mixture of a binder resin, a cathodeconductive material, and a cathode active material; printing, via 3Dprinting, a first anode from an anode filament comprising a mixture ofthe binder resin and an anode conductive material; printing, via 3Dprinting, a first electrolyte from an electrolyte filament comprising amixture of the binder resin and an electrolytic material, wherein thefirst electrolyte is printed between the first anode and the firstcathode; printing, via 3D printing, a cathode bus and a cathode currentcollector within the first cathode from a filament comprising a mixtureof the binder resin and a conductive additive; printing, via 3Dprinting, an anode bus and an anode current collector within the firstanode from the filament comprising a mixture of the binder resin and theconductive additive; and forming a case surrounding at least a portionof the first cathode, the first anode, and the first electrolyte. Thecathode conductive material may comprise LiCoO2. The binder resin maycomprise polyethylene oxide. The anode conductive material may comprisea carbon nanotube having a diameter of approximately 10-9 meters and anaverage length of approximately 1.5 micrometers. The conductive additivemay comprise copper,

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the present disclosure will become moreapparent from the detailed description set forth below when taken inconjunction with the drawings, wherein:

FIG. 1 illustrates a perspective view of an electrochemical cell inaccordance with the present disclosure;

FIG. 2 illustrates a method of forming an electrochemical cell inaccordance with the present disclosure;

FIG. 3A illustrates a cross-sectional view of a partially-formedelectrochemical cell in accordance with the present disclosure;

FIG. 3B illustrates another cross-sectional view of the partially-formedelectrochemical cell of

FIG. 3A, in accordance with the present disclosure;

FIG. 3C illustrates another cross-sectional view of another thepartially-formed electrochemical cell of FIGS. 3A and 3B, in accordancewith the present disclosure;

FIG. 4 illustrates a cross-sectional view of an electrochemical array inaccordance with the present disclosure;

FIG. 5 illustrates a cross-sectional view of another electrochemicalcell in accordance with the present disclosure;

FIG. 6A illustrates a cross-sectional view of an array ofelectrochemical cells in accordance with the present disclosure;

FIG. 6B illustrates a cross-sectional view of another array ofelectrochemical cells in accordance with the present disclosure;

FIG. 6C illustrates a cross-sectional view of yet another array ofelectrochemical cells in accordance with the present disclosure;

FIG. 7A illustrates a perspective view of electrodes of anelectrochemical cell in accordance with the present disclosure;

FIG. 7B illustrates a perspective view of the electrodes of FIG. 7A, inaccordance with the present disclosure;

FIG. 8 illustrates a perspective view of electrodes of anelectrochemical cell in accordance with the present disclosure;

FIG. 9A illustrates a cross-sectional view of an array ofelectrochemical cells in accordance with the present disclosure; and

FIG. 9B illustrates a cross-sectional view of the electrochemical arrayof FIG. 9A, in accordance with the present disclosure.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Persons skilled in the art will readily appreciate that various aspectsof the present disclosure can be realized by any number of methods andarticles configured to perform the intended functions. Stateddifferently, other methods and articles can be incorporated herein toperform the intended functions. It should also be noted that theaccompanying drawing figures referred to herein are not all drawn toscale, but may be exaggerated to illustrate various aspects of thepresent disclosure, and in that regard, the drawing figures should notbe construed as limiting. Finally, although the present disclosure maybe described in connection with various principles and beliefs, thepresent disclosure should not be bound by theory.

The term electrochemical cell refers, throughout the specification andin the claims, to a device capable of receiving, storing, and deliveringelectrical energy, and includes batteries, capacitors, and electric fuelcells.

The terms fuse and fusing refer, throughout the specification and in theclaims, to the physical joining of two materials. For example, fusingcan refer to the joining of polymeric materials through the applicationof heat and/or pressure.

In various embodiments, a method for forming an electrochemical cellcomprises injecting at least one anode, at least one cathode, and atleast one electrolyte into corresponding cavities within a mold. Forexample, an electrochemical cell in accordance with the presentdisclosure can be formed by injecting an anode, a cathode, and anelectrolyte into their corresponding cavities within the mold under heatand pressure in a multi-step injection process. Further, such methodscan be utilized to form arrays of electrochemical cells to produce abattery or capacitor “pack” or assembly. In such embodiments, aplurality of anodes, cathodes, and electrolytes is injected into aplurality of corresponding cavities within a single mold. Suchconfigurations may provide a plurality of individual electrochemicalcells that are electronically coupled to each other and share a singleouter case or wall, eliminating the double wall associated withconventional battery or capacitor packs. Further, such electrochemicalarrays may replace collections of individual batteries which are wiredtogether to provide a desired current and voltage. For example,electrochemical arrays in accordance with the present disclosure mayreplace rechargeable battery packs such as those used by consumerelectronic devices (e.g., laptop computers, tablet computers, andcellular phones), “cordless” tools (e.g., drills, various saws,high-powered flashlights), and uninterrupted power supplies, among otherapplications.

For example, with initial reference to FIG. 1, an electrochemical cell100 (also called a sealed battery 100) comprises an anode 104, a cathode102, and an electrolyte 118 housed within a case 116. In variousembodiments, multiple components of electrochemical cell 100, includingone of more of the anode 104, cathode 102, electrolyte 118, and case 116(among others, which will be described in further detail) may comprisethe same polymeric material. In such embodiments, electrochemical cell100 may exhibit particular benefits, including increased structuralintegrity and/or improved resistance to vibration and force, among otherbenefits.

With initial reference to FIG. 2, a method 200 for making anelectrochemical cell (such as electrochemical cell 100 of FIG. 1) isillustrated. In various embodiments, method 200 comprises a step 201 offorming electrodes. For example, with initial reference to FIG. 3A,cathode 102 and/or anode 104 can be formed in step 201.

In various embodiments, cathode 102 can be injected into a cathodecavity within a mold. Cathode 102 can comprise, for example, a cathodeconductive material contained within a cathode material. For example,cathode 102 can comprise a cathode conductive material homogenously orheterogeneously mixed within the cathode material. In variousembodiments, cathode 102 comprises a suspension of cathode conductivematerial within the solid cathode material. Further, in variousembodiments, cathode 102 may comprise a cathode active material. Forexample, the cathode active material may also be distributed throughoutthe cathode material (similarly to the cathode conductive material).Unlike conventional cathodes comprising a single metal conductiveelement or member, cathode 102 comprises cathode conductive material andcathode active material distributed throughout the cathode material.

In various embodiments, the cathode material of cathode 102 can comprisea non-conductive material. For example, the non-conductive material maycomprise a polymeric material, such as a thermoplastic polymer or athermoset polymer. For example, the cathode material can comprise one ormore of styrene butadiene copolymer, polyvinylidene fluoride,polyurethane, polyvinylchloride, high density polyethylene, polymethylmethacrylate, ethylene vinyl acetate, polyethylene oxide, low densitypolyethylene, and linear low density polyethylene, among other polymericmaterials. In various embodiments, the cathode material (also called a“binder” or “binder resin”) can be in a powder or particulate form. Forexample, a powder or particulate form may allow the cathode material tobe mixed with other materials, such as a suitable cathode conductivematerial and/or a cathode active material, prior to inclusion withinelectrochemical cell 100. In other embodiments, the cathode material maycomprise a liquid into which the cathode conductive material and/orcathode active material can be mixed prior to injection into the mold.

Various cathode conductive materials can be used to form cathode 102. Invarious embodiments, suitable cathode conductive materials comprise oneor more conductive particles or powders, such as a metallic powder, ametallic flake, a metallic ribbon, a metallic fiber, a metallic wire,and a metallic nanotube. For example, the cathode conductive materialcan comprise flakes having thickness between about 0.0001 inch and about0.01 inch, and can comprise rectangular shapes having dimensions ofbetween about 0.01 inch and 0.5 inch. Further, the cathode conductivematerial can comprise wires, fibers, or ribbons having a diameterbetween about 0.001 inch and 0.2 inch, and a length of about 0.01 inchto about 0.15 inch. Such wires, ribbons, or ribbons may have curved,bent, spiral, or otherwise non-straight configurations.

The cathode conductive material can comprise, for example, pre- orpost-consumer recycled material. For example, the cathode conductivematerial can comprise recycled metal material that is mechanicallyreduced to the desired size and geometry. In other embodiments, thecathode conductive material may comprise “fresh,” or non-recycled,material. The powder or particulates of the conductive material can bemixed with the powder or particulates of the cathode material to formthe material of cathode 102 (prior to, and in preparation for, theinjection of cathode 102 into the cathode cavity of the mold). Invarious embodiments, the cathode conductive material becomes suspendedwithin the cathode material, forming cathode 102.

In various embodiments, the cathode conductive material can comprise,for example, lithium and at least one of cobalt, manganese,nickel-cobalt-manganese, and phosphate. The use of any suitable cathodeconductive material is within the scope of the present disclosure. Forexample, further suitable cathode conductive materials include iron,copper, aluminum, nickel, silver, zinc, gold, and palladium. In variousembodiments, the cathode conductive material may comprise between about50% by volume and about 70% by volume of cathode 102.

The cathode active material of cathode 102 can comprise, for example,graphite. In various embodiments, the cathode active material comprisesgraphite between 10% by volume and 30% by volume, and further, between15% by volume and 25% by volume of cathode 102.

Step 201 can comprise, for example, injecting cathode 102 into a cathodecavity within the mold by injection molding. In various embodiments, asuitable cathode material, cathode conductive material, and cathodeactive material are mixed together. The mixture of the materials is theninjected into the cathode cavity of the mold via injection molding,under heat and pressure. For example, the cathode material, cathodeconductive material, and cathode active material can be injected atbetween about 700 psi and about 45,000 psi and further, between about5,000 psi and 23,000 psi, and between about 300° F. and about 650° F.However, any suitable conditions for injecting cathode 102 into the moldare within the scope of the present disclosure.

In various embodiments, step 201 further comprises forming anode 104.For example, similarly to cathode 102, anode can comprise an anodeconductive material contained within an anode material. For example,anode 104 can comprise a conductive material homogenously orheterogeneously mixed within the anode material. In various embodiments,anode 104 comprises a suspension of solid anode conductive materialwithin a solid anode material, which is injected into an anode cavitywithin the mold.

In various embodiments, the anode material of anode 104 can comprise anon-conductive material. For example, the anode material can comprise apolymer, such as a thermoplastic polymer or a thermoset polymer. Similarto the cathode material, the anode material can comprise one or more ofstyrene butadiene copolymer, polyvinylidene fluoride, polyurethane,polyvinylchloride, high density polyethylene, polymethyl methacrylate,ethylene vinyl acetate, polyethylene oxide, low density polyethylene,and linear low density polyethylene, among other polymeric materials. Invarious embodiments, the anode material (also called a “binder” or“binder resin”) can be in a powder or particulate form. In one example,a powder or particulate form may allow the anode material to be mixedwith other materials, such as the anode conductive material. Othersuitable anode materials or cathode materials can comprise epoxy, nylon,acetyl, polycarbonate, and acrylic materials.

In various embodiments, the anode conductive material can comprise oneor more of a graphite powder, a graphite flake, a graphite fiber, and acarbon nanotube. For example, the anode conductive material can compriseflakes having thickness between about 0.0001 inch and about 0.01 inch,and can comprise rectangular shapes having dimensions of between about0.01 inch and 0.5 inch. Further, the anode conductive material cancomprise wires, fibers, or ribbons having a diameter between about 0.001inch and 0.2 inch, and a length of about 0.01 inch to about 0.15 inch.In various embodiments, the anode conductive material can comprisecarbon nanotubes having a diameter of approximately 10⁻⁹ meters and anaverage length of approximately 1.5 micrometers. Although described withreference to specific carbon-based conductive materials and specificgeometries, the use of any suitable anode conductive material is withinthe scope of the present disclosure.

Although described with reference to specific cathode conductivematerials and anode conductive materials, any suitable pairing ofcathode conductive material and anode conductive material having anon-zero electrochemical potential is within the scope of the presentdisclosure. Stated another way, electrochemical cells of the presentdisclosure can include any suitable chemistry, and are not limited tolithium ion batteries. For example, cathode conductive materials caninclude ferrate, iron oxide, cuprous oxide, iodate, metallic oxides(cuprous, cupric, mercuric, cobaltic, manganese dioxide, lead dioxide,silver, nickel dioxide, silver peroxide), oxygen, permanganate, andbromate. These cathode conductive materials can be used with anodeconductive materials such as lithium, manganese, aluminum, zinc,chromium, iron, nickel, tin, lead, hydrogen, copper, silver, palladium,mercury, platinum, and gold.

In various embodiments, the anode conductive material may comprisebetween about 50% by volume and about 90% by volume of anode 104, andfurther, between about 75% by volume and 85% by volume of anode 104.

Cathode 102 and/or anode 104 can comprise a textured interface. Forexample, cathode 102 and/or anode 104 can be formed such that theinterface between the electrodes and electrolyte 118 is non-smooth,rough, jagged, or the like, which may allow for increased surfaceinterface between the electrodes and electrolyte 118. In variousembodiments, cathode 102 and/or anode 104 comprise a textured surfaceformed by manipulating the heat under which the electrode is injected.For example, reducing the heat supplied during injection of cathode 102and/or anode 104 (such as, for example, during step 201 of method 200)may cause particulates of cathode conductive material and/or anodeconductive material to migrate towards one surface of the cathode 102and/or anode 104, creating a textured surface. In other embodiments,texture can be imparted on a surface of cathode 102 and/or anode 104 bythe mold itself. Such textures can be formed, for example, by stippling,sand blasting, or other physical treatment of one or more surfaces ofthe mold, which in turn, imparts a texture to the corresponding surfacesof the cathode 102 and/or anode 104.

In various embodiments, method 200 further comprises a form currentcollectors and current buses step 203. With reference to FIGS. 2 and 3A,step 203 can comprise, for example, forming a cathode collector 106 andcathode bus 110. In various embodiments, cathode collector 106 andcathode bus 110 are made of conductive materials mixed into anon-conductive material (such as a binder or a resin). For example,cathode collector 106 and cathode bus 110 can comprise one or more ofcopper, aluminum, and other metallic materials mixed with anon-conductive material. Cathode collector 106 can comprise a channelwithin cathode 102 comprising conductive material (such as conductivepowder, flakes, foil, and fibers) mixed with the non-conductivematerial. The non-conductive material can comprise one or more resins,such as PVC, PE, PEO, and acrylic. In various embodiments, thenon-conductive material comprises the same material as at least one ofthe anode material, the cathode material, and the electrolyte material.Further, the conductive material can comprise the same material as thecathode conductive material of cathode 102.

Cathode collector 106 and cathode bus 110 can be injected intocorresponding cavities within the mold. In an embodiment, cathodecollector 106 and cathode bus 110 are injected into the moldsimultaneously with cathode 102, anode 104, and/or electrolyte 118. Inother embodiments, cathode collector 106 and/or cathode bus 110 areinjected into the mold before or after cathode 102, anode 104, and/orelectrolyte 118.

Further, step 203 can comprise forming an anode collector 108 and ananode bus 112. In various embodiments, the anode collector 108 and anodebus 112 are made of conductive materials mixed into a binder. Forexample, anode collector 108 and anode bus 112 can comprise one or moreof graphite flakes, powders, fibers, and carbon nanotubes. In oneembodiment, anode collector 108 and anode bus 112 are injected into themold simultaneously with cathode collector 106 and/or cathode bus 110.In other embodiments, anode collector 108 and/or anode bus 112 areinjected into the mold before or after cathode 102, anode 104, and/orelectrolyte 118. Any suitable order of forming components ofelectrochemical cell 100 is within the scope of the present disclosure.

Similar to cathode 102 and anode 104, cathode collector 106 and/or anodecollector 108 can comprise one or more textured surfaces. As previouslydescribed, textured surfaces can be produced by manipulating the heatsupplied during the injection process, and/or imparted by the molditself.

In various embodiments, method 200 comprises a form separators step 205.For example, step 205 can comprise forming one or more separators 114.With reference to FIGS. 2 and 3B, separators 114 can surround andprovide insulation and/or electrical isolation of at least a portion ofcathode 102, anode 104, or electrolyte 118. Separators 114 cancompletely surround cathode 102 and anode 104 to form a sealedelectrochemical cell 100. Further, separators 114 can be formed from anysuitable non-conductive material, such as plastic or a coated orinsulated metal. In various embodiments, separators 114 are formed byinjecting a polymeric material into corresponding cavities within themold. The polymeric material of separators 114 can comprise, forexample, the same material as at least one of the anode material, thecathode material, and the electrolyte material. Further, separators 114can comprise an insulating additive. For example, glass, ceramic,silicones, or other insulating material can be added to the polymericmaterial of separators 114 to improve electrical insulation. Further,separators 114 can comprise one or more openings 222. Openings 222 mayprovide fluid communication to an electrolyte cavity.

Method 200 can comprise, for example, a step 207 of forming anelectrolyte. In various embodiments, step 207 comprises injecting anelectrolyte 118 into one or more electrolyte cavities within a mold. Forexample, electrolyte 118 can be injected through openings 222 and intothe electrolyte cavity. After the injection of electrolyte 118, openings222 can be sealed.

In various embodiments, various steps of method 200 can be performedconcurrently. For example, one or more electrodes (i.e., cathode 102and/or anode 104) can be formed simultaneously with their correspondingcurrent collectors and buses (i.e., cathode current collector 106 andcathode bus 110, and/or anode current collector 108 and anode bus 112,respectively). Stated another way, at least a portion of step 201 can beperformed concurrently with at least a portion of step 203.

Although described with specific reference to method 200, the componentsof electrochemical cell 100 can be formed in various different orders.For example, cathode 102, anode 104, and electrolyte 118 can be injectedinto the cavities of the mold in various different orders. In variousembodiments, cathode 102 and anode 104 can be injected into theirrespective cavities simultaneously, followed by the injection ofelectrolyte 118 into the electrolyte cavity (as illustrated in method200). In other embodiments, electrolyte 118 can first be injected intothe electrolyte cavity, followed by the injection of cathode 102 and/oranode 104 into their respective cavities. However, any order of formingcathode 102, anode 104, and electrolyte 118 within the mold is withinthe scope of the present disclosure.

Similar to cathode 102 and anode 104, electrolyte 118 can comprise anelectrolyte material and an electrolytic material. For example, theelectrolyte material of electrolyte 118 can comprise one or more ofstyrene butadiene copolymer, polyvinylidene fluoride, polyurethane,polyvinylchloride, high density polyethylene, polymethyl methacrylate,ethylene vinyl acetate, polyethylene oxide, low density polyethylene,and linear low density polyethylene, among other polymeric materials. Invarious embodiments, two or more of the anode material, cathodematerial, and electrolyte material comprise, as at least one ingredientin their respective materials, the same non-conductive material. Whilenot intending to be bound by any particular theory, utilizing the samenon-conductive material as a common ingredient for the variouscomponents (anode, cathode, and electrolyte) may allow for fusionbetween the different components, which in turn may reduce voids and/orair trapped between the interfaces of the components.

For example, in one embodiment anode 104 and electrolyte 118 are fusedby the application of heat and/or pressure after injection of anode 104and electrolyte 118 into the mold. In another embodiment, cathode 102and electrolyte 118 are fused by the application of heat and/or pressureafter injection of cathode 102 and electrolyte 118 into the mold. Inanother embodiment, anode 104 and electrolyte 118 are fused and cathode102 and electrolyte 118 are fused.

Fusion of one or more of the electrodes (e.g., cathode 102 and/or anode104) and electrolyte 118 may promote molecular bonding between thecomponents, reducing or eliminating the interface between thecomponents. For example, heat can be applied to electrochemical cell 100after formation, causing many or all of the components of the cell tofuse together. Fusion may reduce the number of gaps and/or amount of airtrapped between the various components, which in turn may improve chargecycle life of the electrochemical cell. In various embodiments,electrochemical cell 100 comprises a continuous, boundary-less,interface-less, or homogeneous polymeric material, wherein the variouscomponents (cathode 102, anode 104, electrolyte 118, etc.) compriseadditional materials (such as conductive materials or active materials)added to the polymeric material and maintained in a desiredconfiguration and geometry. Further, electrochemical cell 100 can beformed without the use of adhesives or compression to join the variouscomponents together and/or to facilitate ion transfer across theinterfaces of the various components.

The electrolyte material of electrolyte 118 can be chosen to perform ina particular environment.

For example, electrochemical cell 100 can be designed to operate inconditions such as high or low heat conditions, high impact, highvibration, or military conditions. Therefore, an electrolyte materialcapable of performing as desired under particular conditions can beselected. In various embodiments, the electrolytic material ofelectrolyte 118 can comprise, for example, one or more of LiBF₄, LiBF₆,LSPS, LiCoO₂, LiOHH₂O, Li₂CO₃, and LiOH.

In various embodiments, one or more of cathode 102, anode 104, andelectrolyte 118 can be formed as premanufactured components, andassembled within electrochemical cell 100. For example, cathode 102 canbe formed in an injection mold and removed for assembly with othercomponents of electrochemical cell 100. In such embodiments, afterassembling the components into electrochemical cell 100, the componentscan be subjected to heat and pressure, allowing the interfaces topartially or fully fuse together.

In yet further embodiments, one or more of cathode 102, anode 104, andelectrolyte 118 can be extruded or pultruded into an initial profile(e.g., rods, sheets, or bars) and machined to a desired shape andconfiguration. After formation of the component, it can be assembled,along with the remaining components, within electrochemical cell 100.

Electrodes such as cathode 102 and/or anode 104 can also be formed, forexample, by molding the mixture of material around a conductive element.For example, cathode 102 can be formed by molding a mixture of cathodematerial (e.g., polymeric material), cathode conductive material, and/orcathode active material around a conductive element. The conductiveelement can comprise a metallic element, such as a strip, rod, or otherphysical shape and configuration. Anode 104 can be similarly formed, bymolding a mixture of anode material (e.g., polymeric material) and anodeconductive material around a conductive element, such as a carbon orgraphite strip, rod, or other physical form.

In various embodiments, method 200 comprises a step 209 of forming acase (also called a “housing”). With initial reference to FIG. 3C, acase 116 can surround and insulate at least a portion of electrochemicalcell 100. For example, case 116 can be injected into the mold before,after, or concurrently with the injection of other components ofelectrochemical cell 100. Similar to separators 114, case 116 cancomprise any suitable non-conductive material, such as a plastic or acoated or insulated metal. For example, case 116 can comprise apolycarbonate, polysulfone, nylon, polyester, and a liquid crystalpolymer. In various embodiments, case 116 comprises the same material asat least one of the anode material, the cathode material, and theelectrolyte material.

With initial reference to FIG. 4, an electrochemical array 440 cancomprise multiple electrochemical cells, such as electrochemical cells400A and 400B. An electrochemical array is defined as a plurality ofelectrochemical cells within a single housing or case. In variousembodiments, cathodes 102 of electrochemical cells 400A and 400B can bein electrical continuity with each other through a single cathode bus110. Further, anodes 104 of electrochemical cells 400A and 400B can bein electrical continuity with each other through a single anode bus 112.In various embodiments, each cell (400A and 400B) of electrochemicalarray 400 can be isolated from each other by separators 114.

With initial reference to FIG. 5, an electrochemical array 500 can alsocomprise a single cathode 102 having a number of cathode extensions 532,and a single anode 104 having a number of anode extensions 534. Invarious embodiments, cathode extensions 532 and anode extensions 534alternate along a specific direction. Electrolyte 118 is injected in thecavity between the cathode extensions 532 and anode extensions 534.Electrochemical array 500 can further be surrounded by a case 116.

With initial reference to FIG. 6A, an electrochemical array 600 cancomprise a plurality of battery cells 650. In various embodiments,battery cells 650 comprise lithium ion battery cells formed inaccordance with any of the previously described methods. For example,electrochemical array 600 may be formed by injecting the anode andcathode of each battery cell 650 simultaneously into plurality of molds,followed by injection of each electrolyte injected into the molds. Eachbattery cell 650 can be connected in parallel to each adjacent batterycell 650 via a shared cathode bus 610 and anode bus 612. In suchembodiments, electrochemical array 600 comprises a plurality of batterycells 650 connected together to provide a single electrical discharge.For example, each battery cell 650 can be electrically coupled to thecathode bus 610 and the anode bus 612.

A case may be injected around each battery cell 650 to prevent shortcircuiting of any of battery cells 650. The entire electrochemical array600 can be placed into a second case. Cathode bus 610 and anode bus 612can be formed simultaneously with the anodes and cathodes. In anembodiment, the temperature of each mold used to form each battery cell650 is adjusted along with the cavity temperature of each mold todetermine the size and depth of cathode bus 610 and anode bus 612. Forexample, by adjusting the mold temperature and cavity temperature,cathode conductive material and anode conductive material injected withthe cathode material and the anode material may form above the areawhere the anode or cathode are formed, forming cathode bus 610 and/oranode bus 612. The temperatures are adjusted using heating and coolingelements such that a predetermined amount of material forms as cathodebus 610 and anode bus 612.

With initial reference to FIG. 6B, electrochemical array 600 cancomprise a plurality of battery cells 650 grouped into arrays with afirst sub-array 622 having battery cells 650 connected in parallel, anda second sub-array 624 having battery cells 650 connected in series. Byarranging a number of sub-arrays in parallel and a number of sub-arraysin series, the overall voltage and current output of electrochemicalarray 600 can be adjusted to a desired level.

With initial reference to FIG. 6C, electrochemical array 600 comprises aplurality of first electrochemical cells 650 and a plurality of secondelectrochemical cells 652. In various embodiments, each of first cells650 and second cells 652 are connected to a cathode switch 634 and anodeswitch 636. Cathode switch 634 and anode switch 636 can be any suitableswitch, such as a surface mounted switch. Cathode switch 634 and/oranode switch 636 can be mounted on a material formed during formation ofelectrochemical cells 650 and 652. A central processing unit (not shown)may monitor the current output or voltage of an individual first cell650 and remove the first cell 650 from electrochemical array 600 shouldthe voltage or current from the first cell 650 fall below apredetermined threshold. In various embodiments, when switches 634 and636 remove a particular first cell 650 from the array, a correspondingsecond cell 652 is connected to cathode bus 610 and anode bus 612.

With initial reference to FIG. 7A, an example electrochemical cell 700is illustrated. Electrochemical cell 700 can comprise a cathode plate702 and an anode plate 704. Cathode plate 702 and anode plate 704 eachinclude a plurality of channels 756 extending along a length of anodeplate 704 and cathode plate 702. For example, the plurality of channels756 may extend through anode plate 704 and/or cathode plate 702 in the xdirection, as indicated by the axes of FIG. 7A. Channels 756 are sizedsuch that a molded wire can be formed in each channel. A plurality ofopenings 758 can be formed across the face of cathode plate 702 andanode plate 704, with each opening 758 being connected to a respectivechannel 756 in cathode plate 702 or anode plate 704 and extending in they direction..

With initial reference to FIG. 7B, conductive pathways 760 are formed inchannels 756. Conductive pathways 760 may be formed by injection moldinga metal material into each channel 756 under pressure. An electrolytematerial may be injected between cathode plate 702 and anode plate 704after conductive pathways 760 are formed. For example, conductivepathways 760 may extend through anode plate 704 and/or cathode plate 702in the x direction, as indicated in the axes of FIG. 7B. Each conductivepathway 760 can connect to a respective anode collector or cathodecollector in the battery 700. By forming a plurality of conductivepathways 760 in anode plate 704 and cathode plate 702, the conduction ofcurrent from each cell 700 is increased.

With initial reference to FIG. 8, an electrochemical cell 800 isillustrated. In various embodiments, electrochemical cell 800 comprisesa cathode plate 802 having a plurality of cathode ridges 872 spacedacross a surface of the plate. Electrochemical cell 800 can furthercomprise anode plate 804 having a plurality of anode ridges 874, each ofwhich correspond to and are offset from each of cathode ridges 872. Invarious embodiments, cathode plate 802 and anode plate 804 arepositioned such that cathode ridges 872 are adjacent to anode ridges874, with a space between the surface of anode plate 804 and the surfaceof cathode plate 802. An electrolytic material can be injected into thespace between cathode plate 802 and anode plate 804. Cathode plate 802and anode plate 804 can be formed by injecting a cathode material and ananode material into the same mold, followed by injection of anelectrolyte material. A case can formed around anode plate 804 andcathode plate 802 to form a sealed battery. By injecting the anode,cathode and electrolyte material under heat (e.g., 300° F.-650° F.) andpressure to form electrochemical cell 800, the surface contact betweenthe anode material, cathode material, and electrolytic material may beimproved, and the charge density of the battery may be increased.

In various embodiments, electrochemical cells of the present disclosurecomprise non-rectangular geometries. With initial reference to FIG. 9A,electrochemical array 900 comprises a plurality of triangular shapedbattery cells 950. With reference to FIG. 9B, each electrochemical cell950 comprises a cathode 902, an anode 904, and an electrolyte 918. Thesides of the triangular shape of each electrochemical cell 950 areformed by a case 916 surrounding anode 904, cathode 902, and electrolyte918. In various embodiments, electrolyte 918 varies in thickness acrossthe length of electrochemical cell 950. Electrochemical cell 950 can,for example, be formed by injecting material of the various components(anode 904, cathode 902, and electrolyte 918) into a mold underpressure, as previously described. In various embodiments, thetriangular geometry may increase the structural strength ofelectrochemical array 900 and/or allow for more intimate nesting ofindividual electrochemical cells 950 to each other, thereby increasingthe density of electrochemical array 900. Such configuration may providefor an electrochemical array 800 that is physically smaller than, yetprovides the same or increased electrical capacity of, electrochemicalarrays of conventional geometries.

Although described with reference to specific geometries (including thetriangular geometries illustrated in FIGS. 9A and 9B), processes of thepresent disclosure may facilitate the formation of electrochemical cellshaving a wide variety of geometries. For example, electrochemical cellsof the present disclosure can be formed having geometries includingarcs, spheres, waves, tubes, trapezoids, and other non-rectangulargeometries. Further, electrochemical cells in accordance with thepresent disclosure may comprise conforming geometries, in which theshape and configuration of the cell conforms to the shape andconfiguration of an independent component or device. For the purposes ofthis disclosure, the term “independent component” means a component thatis independent from the electrochemical cell itself. Further, anindependent component may be a part of a larger article. For example,electrochemical cells of the present disclosure can conform tocomponents of smaller articles such as watch bands, hinges, latches,and/or clips, or components of articles as large as vehicles, includingaircraft, automobiles, motorcycles, bicycles, buses, railed vehicles(e.g., trains), and spacecraft.

Further, electrochemical cells of the present disclosure can comprisecapacitors. In various embodiments, a capacitor such as a platecapacitor can be formed via injection molding of the various components.For example, one or more conductive plates can be formed by injectionmolding a mixture of conductive material and resin. Further, adielectric layer can be formed by injection molding a mixture of thesame resin and a dielectric material. In other embodiments, injectionmolded conductive plates can be used in conjunction with non-polymeric(e.g., ceramic, paper, glass) dielectric materials.

Although described with reference to molding and, specifically,injection molding, other methods of forming electrochemical cells,including additive manufacturing/three-dimensional (3D) printingtechniques, are within the scope of the present disclosure.

For example, an electrochemical cell (such as, for example,electrochemical cell 100) can be formed using a 3D printing techniquesuch as, for example, fused filament fabrication (also referred to asFused Deposition Modeling, registered to Stratasys, Inc.). In variousembodiments, components of electrochemical cell 100, including anode104, cathode 102, and/or electrolyte 118, among others, can be formedusing fused filament fabrication. For example, one or more componentscan be formed by using fused filament fabrication to form the componentsinside of a pre-formed housing 116. In other embodiments, one or morecomponents can be formed independently of housing 116 using fusedfilament fabrication, then placed in their respective position withinhousing 116 to form electrochemical cell 100.

In various embodiments, a component of electrochemical cell 100 (forexample, cathode 102) can be formed from a mixed-material filament, thecomposition of which corresponds to the desired composition of thecomponent. For example, cathode 102 can be formed by a 3D printingtechnique which deposits a filament comprising a cathode material (suchas, for example, a suitable binder resin), a cathode conductivematerial, and a cathode active material. Such filaments can, forexample, be formed by mixing a powder or particulate form of the cathodeconductive material (and cathode active material, if required) with asuitable binder resin and forming a filament for use in a 3D printer.Suitable binder resins include, for example, nylon, polyethylene,acrylonitrile butadiene styrene (ABS), polylactic acid (PLA),polycarbonate, polyamide, and polystyrene, among others.

Similarly, anode 104 can be formed from a filament comprising an anodematerial (e.g., a thermoplastic resin), and an anode conductive material(such as, for example, carbon nanotubes). Further, electrolyte 118 canbe formed from a filament comprising an electrolyte material (e.g., athermoplastic resin), and an electrolytic material. Any combination ofmethods for forming components of electrochemical cell 100, includingcombinations of additive manufacturing and injection molding, is withinthe scope of the present disclosure.

In various embodiments, other components of the electrochemical cell,such as cathode bus 110, cathode current collector 106, anode bus 112,and/or anode current collector 108 are formed by 3D printing usingmixed-material filaments. For example, one or more of cathode bus 110,cathode current collector 106, anode bus 112, and anode currentcollector 108 can be formed from a mixed-material filament comprising abinder resin and a metallic additive. In various embodiments, themetallic additive can comprise at least one of copper, iron, aluminum,nickel, silver, zinc, gold, and palladium.

EXAMPLE

An electrochemical cell having a single anode, single cathode, andsingle electrolyte will be formed. The cathode will be made by mixingpolyethylene oxide with flakes of LiCoO₂ (approximately 60% by volume)and graphite (approximately 20% by volume) and injecting the materialinto a cavity of a polypropylene housing. The anode will be made bymixing polyethylene oxide with carbon nanotubes (wherein thepolyethylene oxide comprises approximately 20% by volume) and injectingthe material into a cavity of the same housing. The carbon nanotubeswill have an average diameter of 10⁻⁹ meters, an average length of 1.5micrometers, and a carbon purity of approximately 90%. The cathodecurrent collector and cathode bus will be made by mixing copper withpolyethylene oxide and injecting the material into a channel within thecathode. The anode current collector and anode bus will be made bymixing copper with polyethylene oxide and injecting the material into achannel within the anode. The separators will be formed by injectingpolyethylene oxide into the housing in a cavity around the outer surfaceof the anode and cathode. An opening will be formed within the separatorthat allowed for fluid communication into the cavity between the anodeand the cathode. The electrolyte will be made by mixing polyethyleneoxide with LiBF₄ (approximately 25% by volume) and injecting thematerial through the opening in the separator and into the cavitybetween the cathode and anode. A case will be formed by injectingpolypropylene around the outer surface of the cathode bus and the anodebus.

The present disclosure includes methods for forming an electrochemicalcell comprising injecting a mixture of a cathode material and a cathodeconductive material into a first cavity of a mold under heat andpressure to form a first cathode, injecting a mixture of an anodematerial and an anode conductive material into a second cavity of themold under heat and pressure to form a first anode, injecting a mixtureof an electrolyte material and an electrolytic material between thefirst anode and the first cathode under heat and pressure to form afirst electrolyte, wherein the first electrolyte is in contact with thefirst cathode and the first anode, and forming a case surrounding atleast a portion of the first cathode, first anode, and firstelectrolyte. The method can further comprise at least one of the stepsof forming a second cathode and forming a second anode. The first anodecan be positioned between the first cathode and the second cathode. Thecathode material and the anode material can comprise at least one ofstyrene butadiene copolymer, polyvinylidene fluoride, polyurethane,polyvinylchloride, high density poly ethylene, polymethyl methacrylate,ethylene vinyl acetate, polyethylene oxide, low density polyethylene,and linear low density polyethylene. The cathode conductive material cancomprise at least one of a metallic powder, a metallic flake, a metallicribbon, a metallic fiber, a metallic wire, and a metallic nanotube, andcan comprise between about 50 and 70 percent by volume. Further, thecathode conductive material can comprise a combination of lithium and atleast one of cobalt, manganese, nickel-cobalt-manganese, and phosphate.The anode conductive material can comprise at least one of a graphitepowder, a graphite fiber, and a carbon nanotube, and may be betweenabout 75 and 85 percent by volume of the first anode. The electrolytecan comprise at least one of LiBF₄, LiBF₆, LSPS, LiCoO₂, LiOHH₂O,Li₂CO₃, and LiOH. The case can comprise a non-conductive thermoplasticmaterial.

In the present disclosure, the words “a” or “an” are to be taken toinclude both the singular and the plural. Conversely, any reference toplural items shall include, where appropriate, the singular.

Numerous characteristics and advantages have been set forth in thepreceding description, including various alternatives together withdetails of the structure and function of the devices and/or methods. Thedisclosure is intended as illustrative only and as such is not intendedto be exhaustive. It will be evident to those skilled in the art thatvarious modifications may be made, especially in matters of structure,materials, elements, components, shape, size, and arrangement of partsincluding combinations within the principles of the invention, to thefull extent indicated by the broad, general meaning of the terms inwhich the appended claims are expressed. To the extent that thesevarious modifications do not depart from the spirit and scope of theappended claims, they are intended to be encompassed therein.

We claim:
 1. An electrochemical cell comprising: a first cathodecomprising a cathode conductive material and a cathode active materialsuspending within a binder resin, wherein the cathode conductivematerial comprises between 50 and 70 percent by volume of the firstcathode; a first anode comprising an anode conductive material suspendedwithin the binder resin, wherein the anode conductive material comprisesbetween 75 and 85 percent by volume of the first anode; a firstelectrolyte positioned between and in contact with the first cathode andthe first anode and comprising an electrolytic material suspended withinthe binder resin; and a case surrounding at least a portion of the firstcathode, a portion of the first anode, and a portion of the firstelectrolyte.
 2. The electrochemical cell of claim 1, wherein the cathodeconductive material comprises at least one of metallic powder, ametallic flake, a metallic ribbon, a metallic fiber, a metallic wire,and a metallic nanotube.
 3. The electrochemical cell of claim 1, whereinthe cathode conductive material comprises lithium and at least one ofcobalt, manganese, nickel-cobalt-manganese, and phosphate.
 4. Theelectrochemical cell of claim 1, wherein the binder resin comprises atleast one of styrene butadiene copolymer, polyvinylidene fluoride,polyurethane, polyvinylchloride, high density poly ethylene, polymethylmethacrylate, ethylene vinyl acetate, polyethylene oxide, low densitypolyethylene, and linear low density polyethylene.
 5. Theelectrochemical cell of claim 1, wherein the cathode conductive materialcomprises at least one of a wire, a fiber, and a ribbon, and wherein thecathode conductive material comprises a diameter of between about 0.001inch and about 0.2 inch and a length of between about 0.01 inch andabout 0.15 inch.
 6. The electrochemical cell of claim 1, wherein theanode conductive material comprises a carbon nanotube having a diameterof approximately 10⁻⁹ meters and an average length of approximately 1.5micrometers.
 7. The electrochemical cell of claim 1, wherein theelectrolytic material comprises at least one of LiBF₄, LiBF₆, LSPS,LiCoO₂, LiOHH₂O, Li₂CO₃, and LiOH.
 8. The electrochemical cell of claim1, further comprising a cathode bus and a cathode current collectorwithin the first cathode and an anode bus and an anode current collectorwithin the first anode.